1. Field of the Invention
The present invention relates to a process of producing a catalyst plate, and particularly to a process suitable for continuously mass-producing catalyst plates in each of which a catalytic substance is deposited on a substrate of an expanded metal plate, and a system for use in the process.
2. Description of the Prior Art
Heretofore, there has been known to use a catalyst plate for the denitration of exhaust gas in which a catalytic substance is applied to an expanded metal plate. The expanded metal plate of the type described is produced such that, as shown in FIG. 2, a thin metal plate 16 is formed therein with slits by means of a blade 90, and expanded to form therein meshes. In this case, however, there should necessarily occur differences in length due to differences between meshes in opening degree, with the result that tongue portions 16A are formed at the forward end portion of the expanded metal plate and further the expanded metal plate is curved. The differences between meshes in opening degree are attributed to errors in accurracy of working by use of a working machine and the blade 90, frictions at the sliding surfaces of the machine, the degree of sharpness of the blade 90, the variability in thickness of the material and the like. Consequently, as shown in FIG. 3, in general, the blade 90 is divided into two or more blade portions and cutting depth `a` by the blade portions 90A, 90B and 90C is made adjustable. However, as described above, the causes for generating differences between meshes in opening degree are varied and composite, and moreover, the adjustment of the blade 90 is very difficult to do, thereby necessarily causing distortions to the expanded metal plate thus produced.
To remove the above-described distortions, there has been used a roll leveller in which the metal plate is clamped by three rotary rolls, with one of the rolls contacting the upper surface of the metal plate and the two others contacting the lower surface thereof, and allowed to be passed therethrough. Nevertheless, the above-described roll leveller has principally functioned to correct irregular curls in the metal plate and could correct few distortions in the metal plate due to the differences between meshes in opening degree. In particular, when the metal plate is not shorn into pieces of short length during production process but wound for use, developments of curves in the widthwise direction and tongue portions in the metal plate due to the accumulation of the distortions have been remarkable, whereby difficulties have been encountered in producing the product by use of the above-described roll leveller, thereby deteriorating the material quality of the product.
On the other hand, there has been known a method wherein the metal plate is shorn into pieces of short length or substrates, a catalytic substance is applied to the substrate thus produced, and formed into a catalyst having a predetermined form. However, according to this method, each of the substrates is handled separately, many aspects of the production process resort to manual operations, and a large number of man-hours is required for the handling of the substrates, whereby the variability in the products produced is wide, making it difficult to apply the method to the mass production.